Probiotics increase intramuscular fat and improve the composition of fatty acids in Sunit sheep through the AMPK signaling pathway

This experiment aims to investigate the impact of probiotic feed on growth performance, carcass traits, plasma lipid biochemical parameters, intramuscular fat and triglyceride content, fatty acid composition, as well as mRNA expression levels of genes related to lipid metabolism and corresponds to the activity of the enzyme in Sunit sheep. In this experiment, 12 of 96 randomly selected Sunit sheep were assigned to receive the basic diet or the basic diet supplemented with probiotics. The results showed that supplementation with probiotics significantly increased the loin eye area, and decreased plasma triglycerides, low-density lipoproteins, and free fatty acids, increasing the content of intramuscular fat and triglycerides in the muscle and improving the composition of the fatty acids including arachidonic acid, γ-linolenic acid, eicosapentaenoic acid, and so on. Furthermore, the inclusion of probiotics in the diet reduced the expression of AMPKα2 mRNA and CPT1B mRNA , while increasing the expression of ACCα mRNA, SREBP-1c mRNA, FASN mRNA, and SCD1 mRNA. The results of this study indicate that the addition of probiotics to the diet regulates fat deposition and improves the composition of fatty acids in Sunit sheep through the signaling pathways AMPK-ACC-CPT1B and AMPK-SREBP-1c. This regulatory mechanism leads to an increase in intramuscular fat content, a restructuring of muscle composition of the fatty acids, and an enhancement of the nutritional value of meat. These findings contribute to a better understanding of the food science of animal resources and provide valuable references for the production of meat of higher nutritional value.